Lupin the Third: Blood Seal of the Eternal Mermaid 2011 ( 6.182)

A gemstone named the Mermaid's Scale appears in a secret, underground auction, and Lupin is coerced by the queen of the underworld into stealing the rock for her. Lupin however quickly discovers not only that the stone is a forgery, but that the real Mermaid's Scale is part of an unsolved riddle involving the mysterious girl Misa that leads to transcending mortality.